120 L. HILLIS-COLINVAUX 



Type specimen. Ellice Islands, Funamanu, dredged —72 m, 

 No. A 54, Funafuti Expedition, 1896-1898 (BM box coll. 196, as 

 H. opuntia f. elongata). 



Habitat. Attached to rock surfaces where it may grow from 

 between the plates of corals, or as pendant fronds beneath coral 

 overhangs. Its range is from about — 10 m to — 100 m. In Jamaica 

 it reaches its greatest development on the fore-reef slope (Goreau 

 and Goreau, 1973), and is associated with H. cryptica at this and 

 greater depths. In the lagoon of Enewetak Atoll, it is a common 

 Halimeda of the pinnacles. 



Geographic distribution. Western Indian Ocean; western Pacific, 

 both north and south ; north-western Atlantic. 



Halimeda distorta (Yamada) L. H. Colin vaux 

 Figure 34. 



Halimeda distorta L. H. Colinvaux (1968a), p. 33, Figs 4, 6. 



Halimeda incrassata f. distorta Yamada (1941), p. 119, Fig. p. 120; Yamada 



(1944), p. 28, Plate 4. 

 Halimeda opuntia v. hederacea (Barton) Hillis p.p. (1959), p. 360. 



Plants to at least 26 cm long, sometimes bushy, with prostrate and erect 

 portions and a diffuse holdfast region (i.e. not restricted to single basal 

 region) ; calcification heavy ; branching in more than one plane from succes- 

 sive segments, usually di- and trichotomous ; segments often ribbed, 

 sometimes keeled, very commonly contorted, brittle; segment shape 

 commonly broadly ovate to discoidal, the lower margins truncate to 

 auriculate and sometimes somewhat cuneate, upper margins smooth to 

 moderately lobed; segments to 16 mm long, 19 mm wide. 



Cortex of up to several series of utricles with inner ones usually not 

 utriculiform ; outermost utricles attached but slightly after decalcification, 

 frequently tending to separate at least in patches, but retaining their 

 polygonal shape in surface view, diameter in surface view 36-60 [im, in 

 section outermost utricles 39-54(-62) [im long, not more than four supported 

 by each secondary utricle; secondary utricles 17-37 [xm broad. 



Medullary filaments numerous in mature segments, commonly united at 

 the node in pairs for a relatively short distance; complete fusion in pairs, 

 short and complete fusion in threes and occasionally other groupings, or the 

 filaments completely separate; short fusion for the distance of (66-) 100- 

 160(-193) [j.m; nodal units may be entangled and adhere firmly; medullary 

 filaments above the node sometimes not developing a cortex but continuing 

 as long, sometimes tangled, threads. 



Type specimen. Caroline Islands, near Ponape, lagoon of Ants 

 Atoll, Y. Yamada, S 15-1 (SAP). 



